FISHERIES RESEARCH INSTITUTE,MOA,TAIWAN

In order to understand the temporal and spatial distribution of larval cutlassfish (genus: Trichiurus) in the surrounding waters of Taiwan, 11 quarterly cruises were conducted in the 62 sampling stations in those waters from 2007 to 2009. A total of 229 samples of larval cutlassfish (Trichiurus) were collected by using an ORI net. Trichiurus larvae were most abundant in spring (133 samples). In spring, higher levels of abundance were mainly found in the Taiwan Strait and northern waters off Taiwan, and lower levels of abundance were found in the southwestern waters and eastern coastal waters. In winter, the larvae were mainly collected in the northern and northeastern waters of Taiwan, with smaller levels of abundance in the Taiwan Strait and southwestern waters. No obvious distribution patterns were found in summer and autumn. Correlation analyses indicated a greater distribution of larvae in waters with lower temperature in spring and summer, which was related to the upwelling of cold water. However, the abundance of larvae was positively correlated with zooplankton and phytoplankton in winter, spring, and summer, which was related to the feeding. In conclusion, the abundance of Trichiurus larvae varied seasonally and annually, and the spawning peak was in spring. The distribution pattern of Trichiurus larvae was possibly influenced by the seasonality of oceanic environments caused by the fluctuation of cold and warm water masses in the waters around Taiwan.